I'm afraid I am responsible for Shelly going missing. An error in the app I was using caused me to log Shelly as Discovered instead of Found on 09/02/2017. Thinking the TB was in my inventory, I then traveled to Italy and dropped Shelly into GC4PNC9, in Piedmont, Italy on 10/01/2017. (I think that is the correct cache, but I cannot be 100% certain. I have photos of the TB at GC4PNC9 which I will attach to this note.)
When I tried to log the TB that evening, I could not "drop" it because it was not in my inventory and I did not have the trackable number. I sent a message to the owner and asked for the trackable ID so that I could fix my errors, but I never received a response.
Hopefully someone has picked up Shelly and will log it. In the meantime, I hope she is enjoying Italy!